Method for the control of a thin film transformer for the execution of logical operations



y 1970 KARL-HEINZ WALTER 3,510,673

METHOD FOR THE CONTROL OF A THIN FILM TRANSFORMER FOR THE EXECUTION 0F LOGICAL OPERATIONS Filed Feb. 13. 1967 ATTYS.

United States Patent METHOD FOR THE CONTROL OF A THIN FILM TRANSFORMER FOR THE EXECUTION OF LOGI- CAL OPERATIONS Karl-Heinz Walter, Munich, Germany, assignor to Siemens Aktiengesellschaft, Munich, Germany, a corporation of Germany Filed Feb. 13, 1967, Ser. No. 615,628 Claims priority, applicatigrzr (Ge6rmany, Feb. 16, 1966,

Int. Cl. Gllc 11/14; H01 f 40/00; H031: 19/168 US. Cl. 307-88 4 Claims ABSTRACT OF THE DISCLOSURE The invention relates to a transformer which, by reason of its considerably simplified manner of production, is especially suited for memory storers, and may serve for the linking of several input or word lines with one output or signal line, in which arrangement the current pulse supplied to an input line, in dependence on the current flowing in a control line, either appears at the output line or is prevented from so doing.

A known transformer of this type has a hollow cylinder covered with a magnetizable layer, provided with a circular magnetic preferential direction, and is enclosed by at least one input line or word line, which cylinder is concentrically penetrated by control, and output lines or signal lines.

A current pulse fed into the input line or one of the input lines generates a magnetic field axially aligned to the hollow cylinder, which field, in the absence of a control current of suflicient magnitude, brings about a change of the direction or magnetization of the magnetic layer, i.e., a turnabout of the magnetization from the preferential direction into the direction of the magnetic field of the input current pulse, and thereby the occurrence of a signal on the output line.

The magnetic fields generated in the word or input and control lines are, in this known arrangement, aligned perpendicularly to one another, for which reason there is always present a magnetic field component acting in the direction of the longitudinal axis of the hollow cylinder, which component endeavors to evoke at least a small magnetization change in this direction and thereby an interference signal. This undesired magnetization change can be largely suppressed by large control currents. Large control currents, however, in rapid digital data processing technology in particular, are very expensive to produce, for which reason they are avoided as far as possible.

The present invention has as its primary problem that of creating a method of controlling a transformer for the execution of logical operations which, aside from a particularly suitable manner of operation, makes possible an increased blocking pass ratio with low signal interference and considerably reduced control current, as well as a relatively easy realizability, without especially high demands on the magnetic characteristics of the magnetizable layer. The method may, if necessary, be produced in such a way that the influence of the magnetic ground 3,510,673 Patented May 5, 1970 field or other magnetic interference fields have only an imperceptible effect on the operation of the transformer.

For the solution of these problems the invention provides, in a method of the type initially mentioned, that before the feeding in of a word pulse, i.e., a current pulse into one of the input lines, the direction of magnetization of the layer is selectively switched into blocking position parallel to the longitudinal axis of the hollow cylinder, or into a pass position inclined with respect thereto. As a result, in the blocking position of the transformer a word pulse or the magnetic field axially aligned to the hollow cylinder, evoked by this pulse, cannot produce any change in the direction of the magnetization of the layer, and therefore neither can it produce any signal in the output line. In distinction thereto, in the switching of the transformer into pass position or through the alignment of magnetization of the layer inclined to the hollow cylinders longitudinal axis, a current pulse conducted on one of the word or input lines will generate an output signal of sufiicient magnitude.

According to a further proposal according to the invention, the preferential axis of magnetization of the magnetic layer of the hollow cylinder can be aligned circularly, in which case, at least in the blocking or rest position, the direction of magnetization of the layer, under the effect of a constant magnetic field aligned axially to the hollow cylinder, extends parallel to the long axis of the hollow cylinder. A current pulse conducted through one of the word or input lines, in this alignment of the magnetization, yields no signal in the output line. If a current pulse fed into one of the word or input lines is to generate a signal, then there is supplied to the control line a so-called activation current which turns the direction of magnetization out of the direction compelled by the constant magnetic field, whereby there appears a signal in the output line. If a constant magnetic field is used in the operation of the transformers, according to the invention, this can be arranged in common to all the cylinders of a matrix.

Instead of a constant magnetic field in the direction of the longitudinal axis of the hollow cylinder there can also be utilized a magnetic anisotropy in this direction.

Furthermore, it is also possible to use a magnetically isotropic layer in which, at least in blocking or rest position, the direction of magnetization of the layer runs parallel to the longitudinal axis of the hollow cylinder under the effect of a constant magnetic field. The manner of operation of this and of the aforementioned transformer corresponds to that above set forth.

For the explanation of the process according to the invention as well as of the transformers used for this, reference is made to the drawings, wherein like reference characters indicate like or corresponding parts, and in which:

FIG. 1 illustrates schematically a transformer circuit which may be utilized in connection with the practice of the invention, in which the magnetizable layer has a circularly aligned preferential direction of magnetization;

FIG. 2 is similar to FIG. 1 and illustrates a transformercircuit in which the magnetizable layer has a preferential direction of magnetization which is aligned parallel to the longitudinal axis of the hollow cylinder;

FIG. 3 is similar to FIG. 1 and illustrates a transformer circuit in which the magnetizable layer is magnetically isotropic; and

FIG. 4 is a series of three coordinated charts in which: chart (:1) illustrates the current pulses in the input line; chart (b), oriented with respect to chart (a), illustrates a current pulse on the control line; and chart (c), oriented with respect to charts (a) and (b), illustrates an output signal.

Referring to FIG. 1, the transformer 1 is covered with a magnetizable layer, whose preferential axis of magnetization is circularly aligned according to arrow B. The transformer 1 is encircled by a word or input line 2, which may be traversed by a word current I The transformer 1 is concentrically threaded by control and output or signal lines 3 and 4, respectively, in which the line 3 may be traversed by a control current I and in its output line 4, under certain conditions there is generated an output signal U In the direction of the longitudinal axis of the hollow cylinder there exists a constant magnetic field applied in the direction of the arrows A. In the trans former according to FIG. 2, instead of the constant magnetic field there exists a preferential axis C of magnetization aligned parallel to the longitudinal axis of the hollow cylinder. In distinction to both of these examples, the magnetic layer of the transformer according to FIG. 3 is magnetically isotropic, in which system at least in the blocking or rest position of the transformer the direction of magnetization of the layer runs parallel to the longitudinal axis of the hollow cylinder under the effect of a constant magnetic field A aligned axially with respect to the hollow cylinder.

The manner of operation of the transformers according to FIGS. 1 to 3, as well as the method of the invention for the operation of these transformers are illustrated in charts (a), (b) and (c) of FIG. 4, in which there are plotted over time (abscissa) current pulses supplied to the word or input line (see chart (a)) and a control current supplied to the control line (see chart (11)). Chart illustrates the output signal U occurring, with corresponding controlling of the transformer, in the output line 4.

Changes may be made within the scope and spirit of the appended claims which define what is believed to be new and desired to have protected by Letters Patent.

I claim:

1. A method of controlling the transmission of signals tion parallel to the longitudinal axis of the hollow cylinder, or a pass position inclined to such axis, and applying an input pulse to the input line while the direction of magnetization remains in the selected state, whereby the simultaneous appearance or nonappearance of a corresponding pulse in the output line is determined by such direction of magnetization and wherein the direction of magnetization of said magnetizable layer, in the absence of a signal on said control line, is in a blocking position, and transmission of an input pulse is efiected by the simultaneous application of an impulse on said control line and an impulse on said input line.

2. A method according to claim 1, wherein the magnetizable layer has a preferential direction of magnetization which is circularly aligned, and applying a constant magnet field aligned axially with respect to the hollow cylinder, whereby the direction of magnetization of the layer extends, at least in blocking or rest position, parallel I to the longitudinal axis of the hollow cylinder.

I parallel to the longitudinal axis of the hollow cylinder.

from an input line to an output line of a transformer, for 1 the execution of logical operations, which comprises a 4 References Cited UNITED STATES PATENTS 3,047,423 7/ 1962 Eggenberger 117-107 3,221,312 11/ 1965 MacLachlan 340-174 3,223,986 12/1965 Clark 340174 3,264,619 8/1966 Riseman 340174 3,298,005 1/1967 .Matick 340174 3,278,914 10/ 1966 Rashleigh 340174 BERNARD KONICK, Primary Examiner K. E. KROSIN, Assistant Examiner U.S. Cl. X.R. 340-174 

